In the field of laser entertainment, many methods have been used to project and display the unique properties of laser light. Due to the intensity of laser light, the purity of its color, its coherence and minimal beam divergence, lasers have been used to create aesthetically pleasing displays of abstract and graphic art.
Heretofore, there have been various methods of displaying laser light for entertainment. The most common method is to project image patterns created by scanning, diffracting or diffusing laser light onto an imaging surface, for example, a screen, wall, or other diffusely reflective surface.
One may create a 3-dimensional display by projecting scanned, diffracted, or directed laser light beams into or through a particulate medium like smoke or fog suspended in the air. With this method, the light beam becomes visible wherever it illuminates the suspended particulates. This creates a 3-dimensional effect. Without such suspended particulates, the laser light beam is invisible or difficult to see in the air.
This invention is a departure from and has significant advantages over the particulate method of 3-dimensional laser display. The invention uses plural layers of partially transmissive and partially diffusely reflective material. These layers of material act as fixed, multi-planar imaging elements for laser light patterns projected onto and through them.
Previous attempts to contain and control particulates, like smoke, within an enclosed display device or area have proven futile because the particulates settle on the floor or walls of any container, making it progressively harder to view the image inside.
The only practical way to use a particulate medium is to constantly refresh the supply of particulates in an open area. This is at best messy and unhealthful in that it requires viewers of the display to breathe the often unpleasant particulate supply when the display is indoors. It is difficult to use particulate laser displays as a consumer product without filling a room with smoke or fog, or building a complex device to prevent deposition of particulate on the walls of a display box.
Outdoor displays which depend on natural atmospheric conditions are unreliable in that the suspension of water vapor or particles in the air varies widely. A display may look good one night and be barely visible the next. Indoors there is rarely enough natural suspension of water vapor or airborne particles to make 3-dimensional laser displays practical. In both indoor and outdoor environments regardless of ambient particle suspension, large amounts of laser power are necessary to create a visible 3-dimensional display. Lasers needed for such displays are very expensive, costing tens of thousands of dollars. This fact places 3-dimensional laser displays out of the range of consumer pricing and at a very high level for commercial or industrial applications.
Recently, highly collimated incandescent light sources have been used for similar entertainment purposes, i.e., scanning and directing beams for display. The same difficulties of display and viewing are present for these non-laser beams as for lasers. In fact the problems are compounded since even the most collimated of non-laser light sources still has a large beam divergence.